DESCRIPTION: This application describes three related studies of tooth fracture, a condition that affects an estimated five percent of adults annually. Despite its relatively frequent occurrence, the phenomenon has not been examined in any detail. Consequently, there are no direct estimates of the incidence of this condition. In addition, risk indicators for tooth fracture are poorly understood. Finally, the distributions of treatments fractured teeth receive, and the short-term outcomes of these treatments are completely unknown. This profound lack of information notwithstanding, a substantial portion of re-restoration in the nation s dental practices consists of placing crowns for the purpose of preventing tooth fracture, accounting for estimated expenditures of one billions dollars annually. The proposed studies examine tooth fracture in two adult populations-- enrollees in a dental HMO in Portland, OR, and army personnel stationed at Ft. Hood, TX. At both sites, preliminary estimates of the incidence of tooth fracture overall and by tooth type will be established by noting all tooth fracturing in these populations over periods of 6 and 3 months, respectively. Approximately 400 fracture events will be recorded at each site. A group of risk indicators for the complete fracture of a cusp of a posterior tooth will be examined in identical 12-month case-control studies. At each site, 400 cases will be selected together with 400 matched control teeth from the same patients, and 400 partially matched control patients. Differences in exposure for a variety of clinical, behavioral, demographic, and utilization variables will be determined. The severity of fractures and short-term outcomes of treatment for fractures are determined from incidence and case-control study data and analysis of port-fracture treatment. The information on risk indicators, incidence, severity and short-term outcomes that will result from this study is crucial for subsequent evaluation of approaches to the prevention of tooth fracture. Not only do dentists have no information upon which to base specific absolute and/or risk estimates for individual patients, but also the profession lacks the information upon which to base assessments of the appropriateness of current approaches to the prevention of fracture.